FF error code: this indicates a problem with the freezer fan rotateing.
If the fan has been “whirring” for some time and has now stopped it may be due to ice build up catching the blades.
Try defrosting by switching of for 24 hours with the door open on the freezer. If this cures the fault but problem returns it may be due to a defrost problem.Engineer may be required
FS error code: freezer sensor issue
Try powering off and on to see if problem clears. if continuose you may need to replace sensor.